This invention relates to method and apparatus for feeding a conductive wire when a slide fastener chain provided with a conductive wire for anodizing process is produced. More particularly, the invention relates to improved method and apparatus by which a conductive wire can reliably be secured to the beaded portion of a slide fastener tape without breaking the wire.
Heretofore, U.S. Pat. No. 2,989,444 is known to show a device for feeding a conductive wire for anodizing process of a slide fastener chain. In this device, the wire is guided by a curved tubular fixed guide from a place spaced from the beaded portion of a fastener tape to a point adjacent the beaded portion, where it is secured to the beaded portion by an element to be fixed to the beaded portion. The device is adapted so that the conductive wire is advanced by rollers operating synchronously with the feeding movement of the tape. In such device, the portion of the conductive wire adjacent the beaded portion of the tape is a little tautened by frictional drag imparted from the curved tubular fixed guide. In this condition, when a fastener element is fixed to the beaded portion, the beaded portion deforms clamped by the legs of the element making the sections of the beaded portion between adjacent elements bulge. This results in increased tension in the portion of the wire extending between these elements and causes possibility of breaking the wire. A break in the wire also occurs when advancement of the tape and the wire is not completely synchronous. Furthermore, the drag imparted to the wire from the fixed guide as the wire is advanced increases the possibility of breaking the wire.